Feature: expand in-progress info for crf-search as seen when debugging is enabled

[stderr-to-devnull]

After enabling the debugging, I saw [INFO] level information relayed during in-progress crf-search which I found quite useful and helpful and would like to see it relayed in an optimal way during normal progress.

The debug info in scope:

[2024-09-04T23:12:21Z INFO ab_av1::command::sample_encode] encoding sample 10/16 crf 18

Desired in-progress extra info: encoding sample 10/16 crf 18

1. It is useful to see how many samples were generated, in my case I use just --sample-every.
2. It is useful to see the sample progress (10/16) for a given crf value, sort of like a secondary progress indicator.

[alexheretic]

Yes I think this would be useful. You can see this info already using ab-av1 sample-encode, crf-search and auto-encode are built on top and didn't have quite as easy access to the info relevant to the sample-encode bit. But it is possible for that to be shared and to add simple info to the other higher level commands.